Open AccessLong term variations in equatorial strato-and mesospheric temperatures
Author(s) -
J. V. M. Naidu,
B. Narasimha Murthy,
Rama Chandrasekhar,
K. V. V. Ramana
Publication year - 1980
Publication title -
mausam
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.243
H-Index - 12
ISSN - 0252-9416
DOI - 10.54302/mausam.v31i3.3795
Subject(s) - stratopause , mesopause , stratosphere , atmospheric sciences , mesosphere , altitude (triangle) , climatology , amplitude , quasi biennial oscillation , environmental science , oscillation (cell signaling) , radiosonde , geology , physics , mathematics , geometry , quantum mechanics , biology , genetics
M-100 Rocketsonde temperature data of Thumba in the 30 to 80 km height range for the period 1971-74 are analysed for studying the long term variations at 5 km altitude intervals. It is observed that the amplitude of the semi-annual oscillation dominates over that of the annual oscillation in the stratosphere and close to mesopause. However, the amplitude of the annual oscillation shows a quasi-peak around 70 Km altitude. The phase of the semi-annual oscillation is observed to propagate downward from mesopause while the phase of the annual component propagates on to either side from the stratopause. From a vertical time-section prepared after filtering out periods greater than 3 months wave disturbances of a few weeks period with vertical scale sizes greater than 20 Km sides are observed. A power spectral analysis shows a dominant period well, above the noise level at 52.5 days above the stratopause. Secondary peaks of lesser significance are observed with periods between 17.5 and 30.0 days.